Parthenocarpy is an excellent agronomic trait that enables crops to set fruit in the absence of pollination and fertilization, and therefore to produce seedless fruit. Although parthenocarpy is widely recognized as a hormone-dependent process, hormone-insensitive parthenocarpy can also be observed in cucumber; however, its mechanism is poorly understood. To improve the global understanding of parthenocarpy and address the hormone-insensitive parthenocarpy shown in cucumber, we conducted a physiological and proteomic analysis of differently developed fruits. Physiological analysis indicated that the natural hormone-insensitive parthenocarpy of ‘EC1’ has broad hormone-inhibitor resistance, and the endogenous hormones in the natural parthenocarpy (NP) fruits were stable and relatively lower than those of the non-parthenocarpic cultivar ‘8419 s-1.’ Based on the iTRAQ technique, 683 fruit developmental proteins were identified from NP, cytokinin-induced parthenocarpic (CP), pollinated and unpollinated fruits. Gene Ontology (GO) analysis showed that proteins detected from both set and aborted fruits were involved in similar biological processes, such as cell growth, the cell cycle, cell death and communication. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that ‘protein synthesis’ was the major biological process that differed between fruit set and fruit abortion. Clustering analysis revealed that different protein expression patterns were involved in CP and NP fruits. Forty-one parthenocarpy-specialized DEPs (differentially expressed proteins) were screened and divided into two distinctive groups: NP-specialized proteins and CP-specialized proteins. Furthermore, qRT-PCR and western blot analysis indicated that NP-specialized proteins showed hormone- or hormone-inhibitor insensitive expression patterns in both ovaries and seedlings. In this study, the global molecular regulation of fruit development in cucumber was revealed at the protein level. Physiological and proteomic comparisons indicated the presence of hormone-independent parthenocarpy and suppression of fruit abortion in cucumber. The proteomic analysis suggested that hormone-independent parthenocarpy is regulated by hormone-insensitive proteins such as the NP-specialized proteins. Moreover, the regulation of fruit abortion suppression may be closely related to protein synthesis pathways.

Heat shock transcription factor (Hsf) is one of key regulators in plant abotic stress response. Although the Hsf gene family has been identified from several plant species, original and evolution relationship have been fragmented. In addition, tea, an important crop, genome sequences have been completed and function of the Hsf family genes in response to abiotic stresses was not illuminated. In this study, a total of 4208 Hsf proteins were identified within 163 plant species from green algae (Gonium pectorale) to angiosperm (monocots and dicots), which were distributed unevenly into each of plant species tested. The result indicated that Hsf originated during the early evolutionary history of chlorophytae algae and genome-wide genetic varies had occurred during the course of evolution in plant species. Phylogenetic classification of Hsf genes from the representative nine plant species into ten subfamilies, each of which contained members from different plant species, imply that gene duplication had occurred during the course of evolution. In addition, based on RNA-seq data, the member of the Hsfs showed different expression levels in the different organs and at the different developmental stages in tea. Expression patterns also showed clear differences among Camellia species, indicating that regulation of Hsf genes expression varied between organs in a species-specific manner. Furthermore, expression of most Hsfs in response to drought, cold and salt stresses, imply a possible positive regulatory role under abiotic stresses. Expression profiles of nineteen Hsf genes in response to heat stress were also analyzed by quantitative real-time RT-PCR. Several stress-responsive Hsf genes were highly regulated by heat stress treatment. In conclusion, these results lay a solid foundation for us to elucidate the evolutionary origin of plant Hsfs and Hsf functions in tea response to abiotic stresses in the future.

The shape of fruits is a critical trait affecting the commercial value and consumer acceptance of horticultural crops. Genetic regulation of fruit shape involves complex interactions among multiple genes and environmental factors. This review summarizes recent advances in understanding the genetic mechanisms controlling fruit shape in several key horticultural crops, including tomato, pepper, cucumber, peach, and grape. We present the identification and characterization of genes and quantitative trait loci (QTLs) that influence fruit shape, focusing on the roles of genes such as OVATE, SUN, FAS, LC, ENO, GLOBE, CsSUN, CsFUL1, CsCRC, PpCAD1, PpOFP1, and VvSUN. This review highlights the importance of hormonal pathways, particularly those involving synthesis and concentration of cytokinins and brassinosteroids in shaping fruit morphology, and explores how these genes interact and form regulatory networks that collectively determine the final fruit shape. This knowledge provides a foundation for developing strategies to improve fruit quality and yield through genetic modification and breeding programs.

Luffa is a genus of tropical and subtropical vines in the Cucurbitaceae family, recognized as an important cultivated commercial vegetable. However, the seeds of the luffa species are considered hard-seeded, and the processes governing seed germination remain understudied. The 9-cis-epoxycarotenoid dioxygenase (NCED) genes, which are critical for seed germination, have not been well characterized in Luffa. In this study, we identified four LaNCED genes in Luffa acutangula and four LcNCED genes in Luffa cylindrica, distributed across four chromosomes in each species. Phylogenetic analysis classified these genes into two subgroups. Gene structure and motif composition analyses revealed both similarities and differences among the NCEDs. Cis-element analysis further revealed that these NCEDs may be involved in growth regulation by modulating the phytohormonal network and responding to stress stimuli. Expression profiling of LcNCED genes during seed germination showed a decrease in LcNCED2 levels, coinciding with an increase in α-amylase activity throughout the germination process. Subcellular localization assays demonstrated that LcNCED2 is localized in the chloroplast. Furthermore, transient overexpression of LcNCED2 in tobacco leaves led to a significant increase in ABA content. Our findings provide a comprehensive genomic characterization of the NCED family in Luffa cylindrica and Luffa acutangula and reveal the functional role of LcNCED2 in regulating ABA levels, which may play a critical role in seed germination.

White-fruited bitter melon is a rare species of Momordica charantia L., valued for its pearl-like white pericarp. However, limited research is available regarding its supporting cultivation techniques and fruit quality. Two-season field trials were performed using ‘Kuzhongle’ as scion to evaluate the applicability of luffa rootstocks and seasonal variation in rootstock-mediated effects. Three luffa inbred lines (SS07, SS11 and SS26) were screened in spring, and the superior SS26 was further compared with the commercial rootstock ‘Yinzhen No.1’ in autumn. All rootstocks increased stem diameters, shortened internodes and promoted female flower formation in spring, but their effects on fruit quality varied among genotypes. SS26 exhibited the highest survival rate and significantly enhanced soluble solid content, water content, crude protein content and vitamin C content, while reducing crude fiber content and titratable acidity content. Seasonal comparison revealed consistent quality-modulating effects of SS26 across seasons, except for crude fiber, with a comprehensive performance comparable to the commercial rootstock. Overall, luffa rootstocks consistently modulate vegetative and flowering traits within a season, whereas their impacts on fruit quality show genotypic differences. SS26 exhibits stable and superior grafting performance, providing important material support for bitter melon rootstock breeding research.

White-fruited bitter melon (Momordica charantia L.) is a rare species of Momordica charantia L, valued for its pearl-like white pericarp. However, limited research is available regarding its supporting cultivation techniques and fruit quality. Two-season field trials were performed using ‘Kuzhongle’ as scion to evaluate the applicability of luffa rootstocks and seasonal variation in rootstock-mediated effects. Three luffa inbred lines (SS07, SS11, SS26) were screened in spring, and the superior SS26 was further compared with the commercial rootstock ’Yinzhen No.1’ in autumn. All rootstocks thickened stems, shortened internodes and promoted female flower formation in spring, with genotypically divergent influences on fruit quality. SS26 exhibited the highest survival rate and significantly enhanced soluble solid content, water content, crude protein content and vitamin C content, while reducing crude fiber content and total acid content. Seasonal comparison revealed consistent quality-modulating effects of SS26 across seasons, except for crude fiber, with a comprehensive performance comparable to the commercial rootstock. Overall, luffa rootstocks consistently modulate vegetative and flowering traits within a season, whereas their impacts on fruit quality show genotypic differences. SS26 exhibits stable and superior grafting performance, providing important material support for bitter gourd rootstock breeding research.